Summer Vacation Mistakes that Can Cost You

If you've been daydreaming about a lazy day on the beach, you're in good company. Summer travel plans are up 17 percent, with more than two-thirds of Americans planning to take a summer vacation in 2013, according to American Express' Spending & Saving Tracker. But while a little rest and relaxation may do your body good, one vacation planning mistake could set your finances back for months to come.

A lot of travelers unintentionally spend more money than they have to, says Jessica Galbraith, author of "50 Things to Know to Travel on a Budget: Tips from Experienced Travelers." No matter how much fun you have while you're away, here are some common vacation-planning money mistakes that can add to your stress level once you get back home.

Taking a buy-now, pay-later approach. It's easy to get caught up in everyday life and forget to save in advance for a vacation. Next thing you know, all your friends are talking about a trip to the Caribbean and you feel tempted to reach for your credit card and join them. But before you do that, consider the long-term consequences. If you take a $2,000 vacation and throw it on the credit card at 18 percent interest and make the minimum monthly payments, it will take you more than 10 years to pay for that trip, says Mike LeClear, director of financial counselors for FinancialHope Counseling and Education of Northeastern Indiana. No vacation is worth that much. Consider planning a staycation near your home instead.

Saying 'no' to free money. Nearly three-quarters of Americans who have frequent flier miles don't know how many they have and more than half don't know how their frequent flier programs work, according to a survey conducted by The Points Guy blog and The Princeton Group. Miles and travel rewards points are worth money. Not only may you have enough miles to get a free plane ticket or one-night hotel stay, but if you understand how the program works, you may be able to increase your vacation savings throughout the year by making certain types of purchases on your travel reward credit cards. For example, users of the U.S. Bank FlexPerks Travel Rewards Visa Signature Card get double the points when they use the card on the category, such as gas or groceries, that they spend the most money on each month.

Failing to plan for the unexpected. Anything can ruin your travel plans. You can get appendicitis in a foreign country, have to cut your trip short because of a family crisis or lose your luggage at the airport. Travel insurance will cover many of these expenses, which can be quite hefty. A $100 travel insurance policy could save you the $20,000 it would cost to airlift you home in an emergency, Galbraith says. Check to see what your travel insurance policy explicitly covers. For example, if you plan to engage in extreme sports on your vacation, such as bungee jumping or surfing, you may need to buy additional coverage for injuries incurred during those activities, Galbraith adds.

Paying for something you already have. Before you buy insurance coverage for your trip, make sure you aren't buying something you already have. Some credit card issuers offer supplemental travel insurance that pays for such things as trip cancellation and lost luggage, so check with your card issuer to see whether you're covered by useful credit card insurance perks. Also check with your health insurance provider to see if your policy covers medical emergencies while you're away. Insurance coverage for a rental car is another expense you may be able to avoid. Your auto insurance policy may already provide insurance coverage for your rental car. Many credit cards also will provide some rental car insurance coverage. However, you must rent the car with the card that offers the benefit and decline the coverage offered by the rental car company, says Sarah Pew, a spokeswoman for Visa.

Using the wrong credit card overseas. Many credit card issuers charge foreign transaction fees for purchases made in a foreign currency or that involve a foreign bank. These fees, which are typically around 3 percent, can add up, particularly if you're making a lot of purchases. However, not all credit cards charge them. Neither Capital One nor Discover charge foreign transaction fees, and some other issuers waive the fees on certain cards geared toward travelers. Make sure you're not racking up foreign transaction fees while you have one of these no-fee cards gathering dust in your wallet.

Forgetting that little things add up. The flight and hotel room may be your most substantial costs, but other expenses can break your budget if you fail to consider them. U.S. airlines made more than $3.5 billion in baggage fees in 2012, and if you're planning to come back with a lot of heavy souvenirs, you may pay more than the average $25 to $35 per bag on the return trip, Galbraith points out. Also consider costs of food, transportation and activities such as theme parks once you get to your destination, says Cristy Cash, director of counseling and education at Consumer Credit Counseling Service of Central Oklahoma. You might even be able to cut down on those costs by looking for a hotel that has a microwave or stove so you can do some of the cooking yourself, Cash adds.

Vacations can be times for fun, relaxation and warm memories -- particularly when you take the money worries out of the equation.

See related: 6 credit card problems that can ruin your summer vacation, Booking via travel websites may affect reward miles, perks, 9 tips for traveling with credit cards, Travel perk: credit card emergency travel assistance